[maccatalyst] Increase iOS compatibility by removing XAMCORE_3_0 (#…

…11238)

`XAMCORE_3_0` was added in tvOS and watchOS where binary compatibility
was not a consideration. The work to update source code for `XAMCORE_3_0`
was also minimal.

The former is not the always the case for MacCatalyst, while the latter
is still true.

Fix #11237 and #11236

src/Makefile

@@ -1207,10 +1207,10 @@ TVOS_TARGETS += \
 #
 
 # MacCatalyst is a variant of iOS, so it defines the iOS variables as well.
-MACCATALYST_DEFINES = -define:IPHONE -define:IOS -define:MONOTOUCH -d:__IOS__ -d:XAMCORE_3_0 -d:__MACCATALYST__ $(APPLETLS_DEFINES) -d:SYSTEM_NET_HTTP
+MACCATALYST_DEFINES = -define:IPHONE -define:IOS -define:MONOTOUCH -d:__IOS__ -d:__MACCATALYST__ $(APPLETLS_DEFINES) -d:SYSTEM_NET_HTTP
 MACCATALYST_GENERATOR=$(BUILD_DIR)/common/bgen.exe
 MACCATALYST_GENERATE=$(SYSTEM_MONO) --debug $(MACCATALYST_GENERATOR)
-MACCATALYST_GENERATED_DEFINES= -d:__MACCATALYST__ -d:XAMCORE_3_0 -d:IOS
+MACCATALYST_GENERATED_DEFINES= -d:__MACCATALYST__ -d:IOS
 
 MACCATALYST_CORE_WARNINGS_TO_FIX=-nowarn:219,618,114,414,1635,3021,$(IOS_WARNINGS_THAT_YOU_SHOULD_FIX)
 MACCATALYST_CORE_DEFINES=$(MACCATALYST_DEFINES) -d:COREBUILD

src/UIKit/UIBarItem.cs

@@ -21,18 +21,6 @@
 
 namespace UIKit {
 	public partial class UIBarItem {
-#if __MACCATALYST__ && !NET
-		// This method exists to improve compatibility with assemblies that reference Xamarin.iOS.dll in Mac Catalyst,
-		// such as Xamarin.Forms. Setting the IsError field to true in the attribute means that everything will work at runtime,
-		// but that nobody can use this method at compile time.
-		// This is disabled in .NET because we won't try to be compatible with Xamarin.iOS.dll in .NET.
-		[Obsolete ("Use the overload that takes a 'UIStringAttributes' instead.", true)]
-		public void SetTitleTextAttributes (UIKit.UITextAttributes attributes, UIControlState state)
-		{
-			using (var dict = attributes == null ? null : attributes.Dictionary)
-				_SetTitleTextAttributes (dict, state);
-		}
-#endif
 
 		public void SetTitleTextAttributes (TextAttributes attributes, UIControlState state)
 		{

tests/xharness/Targets/MacCatalystTarget.cs

@@ -80,7 +80,7 @@ protected override int [] UIDeviceFamily {
 
 		protected override string AdditionalDefines {
 			get {
-				return "XAMCORE_3_0;__MACCATALYST__";
+				return "__MACCATALYST__";
 			}
 		}